Genipin relieves diabetic retinopathy by down-regulation of advanced glycation end products via the mitochondrial metabolism related signaling pathway

作者全名："Sun, Ke-Xin; Chen, Yan-Yi; Li, Zhen; Zheng, Shi-Jie; Wan, Wen-Juan; Ji, Yan; Hu, Ke"

作者地址："[Sun, Ke-Xin; Chen, Yan-Yi; Zheng, Shi-Jie; Wan, Wen-Juan; Ji, Yan; Hu, Ke] Chongqing Med Univ, Affiliated Hosp 1, Dept Ophthalmol, 1 Youyi Rd, Chongqing 400016, Peoples R China; [Li, Zhen] Peoples Hosp Leshan, Dept Ophthalmol, Leshan 400000, Sichuan, Peoples R China"

通信作者："Hu, K (通讯作者)，Chongqing Med Univ, Affiliated Hosp 1, Dept Ophthalmol, 1 Youyi Rd, Chongqing 400016, Peoples R China."

来源：WORLD JOURNAL OF DIABETES

ESI学科分类：CLINICAL MEDICINE

WOS号：WOS:001077460700004

JCR分区：Q1

影响因子：4.2

年份：2023

卷号：14

期号：9

开始页：1349

结束页：1368

文献类型：Article

关键词：Genipin; Human retinal microvascular endothelial cells; Angiogenesis; Vascularization; Secretogranin III; Diabetic retinopathy

摘要："BACKGROUNDGlycation is an important step in aging and oxidative stress, which can lead to endothelial dysfunction and cause severe damage to the eyes or kidneys of diabetics. Inhibition of the formation of advanced glycation end products (AGEs) and their cell toxicity can be a useful therapeutic strategy in the prevention of diabetic retinopathy (DR). Gardenia jasminoides Ellis (GJE) fruit is a selective inhibitor of AGEs. Genipin is an active compound of GJE fruit, which can be employed to treat diabetes.AIMTo confirm the effect of genipin, a vital component of GJE fruit, in preventing human retinal microvascular endothelial cells (hRMECs) from AGEs damage in DR, to investigate the effect of genipin in the down-regulation of AGEs expression, and to explore the role of the CHGA/UCP2/glucose transporter 1 (GLUT1) signal pathway in this process.METHODSIn vitro, cell viability was tested to determine the effects of different doses of glucose and genipin in hRMECs. Cell Counting Kit-8 (CCK-8), colony formation assay, flow cytometry, immunofluorescence, wound healing assay, transwell assay, and tube-forming assay were used to detect the effect of genipin on hRMECs cultured in high glucose conditions. In vivo, streptozotocin (STZ) induced mice were used, and genipin was administered by intraocular injection (IOI). To explore the effect and mechanism of genipin in diabetic-induced retinal dysfunction, reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-d-glucose (2-NBDG) assays were performed to explore energy metabolism and oxidative stress damage in high glucose-induced hRMECs and STZ mouse retinas. Immunofluorescence and Western blot were used to investigate the expression of inflammatory cytokines [vascular endothelial growth factor (VEGF), SCG3, tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1 beta, IL-18, and nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing 3 (NLRP3)]. The protein expression of the receptor of AGEs (RAGE) and the mitochondria-related signal molecules CHGA, GLUT1, and UCP2 in high glucose-induced hRMECs and STZ mouse retinas were measured and compared with the genipin-treated group.RESULTSThe results of CCK-8 and colony formation assay showed that genipin promoted cell viability in high glucose (30 mmol/L D-Glucose)-induced hRMECs, especially at a 0.4 mu mol/L dose for 7 d. Flow cytometry results showed that high glucose can increase apoptosis rate by 30%, and genipin alleviated cell apoptosis in AGEs-induced hRMECs. A high glucose environment promoted ATP, ROS, MMP, and 2-NBDG levels, while genipin inhibited these phenotypic abnormalities in AGEs-induced hRMECs. Furthermore, genipin remarkably reduced the levels of the pro-inflammatory cytokines TNF-alpha, IL-1 beta, IL-18, and NLRP3 and impeded the expression of VEGF and SCG3 in AGEs-damaged hRMECs. These results showed that genipin can reverse high glucose induced damage with regard to cell proliferation and apoptosis in vitro, while reducing energy metabolism, oxidative stress, and inflammatory injury caused by high glucose. In addition, ROS levels and glucose uptake levels were higher in the retina from the untreated eye than in the genipin-treated eye of STZ mice. The expression of inflammatory cytokines and pathway protein in the untreated eye compared with the genipin-treated eye was significantly increased, as measured by Western blot. These results showed that IOI of genipin reduced the expression of CHGA, UCP2, and GLUT1, maintained the retinal structure, and decreased ROS, glucose uptake, and inflammation levels in vivo. In addition, we found that SCG3 expression might have a higher sensitivity in DR than VEGF as a diagnostic marker at the protein level.CONCLUSIONOur study suggested that genipin ameliorates AGEs-induced hRMECs proliferation, apoptosis, energy metabolism, oxidative stress, and inflammatory injury, partially via the CHGA/UCP2/GLUT1 pathway. Control of advanced glycation by IOI of genipin may represent a strategy to prevent severe retinopathy and vision loss."

基金机构："National Natural Science Foundation of China [81870650, 81570832, 81900885]; Science and Technology Program Chongqing [2018GDRC008, XKTS049]"

基金资助正文："Supported by the National Natural Science Foundation of China, No. 81870650, No. 81570832, and No. 81900885; Science and Technology Program Chongqing, No. 2018GDRC008 and No. XKTS049"